The invention generally relates to wireless local area networks (WLAN). In particular, embodiments of the invention relate to power saving for one or more access points (AP) in a WLAN.
Typically, an AP is powered through a wired connection, for example, using inline Power over Ethernet, or by connecting the AP (possibly through a power injector and/or universal power supply) to an alternating current (AC) power outlet. This is also the case with some outdoor installations of APs. However, for other installations, it may be more suitable to use wind- and/or solar- and/or battery-powered APs.
Handoffs from one AP to another will occur as a mobile station moves through the coverage area of a WLAN. In most real-time applications, handoff is initiated once the quality for the AP-mobile station wireless link consistently drops below a vendor-specific threshold, denoted Scan_Threshold. Each handoff, which normally includes both a scanning phase and a handoff execution phase, imposes a temporary disconnection from the network, referred to as handoff latency. For real-time applications, for example, voice over Internet Protocol (VoIP), it is important to minimize this interruption as much as possible.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity.